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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
International General Certificate of Secondary Education
*1223775368*
0654/63
CO-ORDINATED SCIENCES
May/June 2013
Paper 6 Alternative to Practical
1 hour
Candidates answer on the Question paper.
No Additional Materials are required.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name on all the work you hand in.
Write in dark blue or black pen.
You may use a pencil for any diagrams or graphs.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
Electronic calculators may be used.
You may lose marks if you do not show your working or if you do not use appropriate units.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part
question.
For Examiner's Use
1
2
3
4
5
6
Total
This document consists of 19 printed pages and 1 blank page.
IB13 06_0654_63/3RP
© UCLES 2013
[Turn over
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1
A student did an experiment to investigate the effect of temperature on the rate of
respiration of yeast. This was done by measuring the rate at which the yeast produced
bubbles of carbon dioxide. Yeast is able to respire, and produce carbon dioxide, even in the
absence of oxygen.
Apparatus was set up as shown in Fig. 1.1.
delivery tube
thermometer
liquid
paraffin
water bath
yeast and sugar
suspension
water
Fig. 1.1
The student made sure that the temperature of the water bath was 20 °C, and then waited
for three minutes. After this time, the number of bubbles produced was counted each
minute for three minutes.
The procedure was then repeated at 30 °C, at 40 °C, at 60 °C, and finally at 80 °C.
The results are shown in Table 1.1.
Table 1.1
number of bubbles in one minute
temperature / °C
1st minute
2nd minute
3rd minute
20
3
5
4
30
10
7
7
40
15
13
19
60
15
16
14
80
0
0
0
average
4
0
(a) Complete Table 1.1, by working out the average numbers of bubbles produced per
minute at 30 °C, 40 °C, and 60 °C giving each of your answers to the nearest whole
number.
[1]
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For
Examiner's
Use
3
(b) On the grid below, plot the average number of bubbles per minute against temperature.
Join your points with straight lines.
For
Examiner's
Use
average
number bubbles
per minute
temperature / °C
[2]
(c) Suggest explanations for
(i) the change in rate of bubble production between 20 °C and 40 °C,
[1]
(ii) the result obtained at 80 °C.
[1]
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(d) Explain why
For
Examiner's
Use
(i) the student waited three minutes before taking readings at each temperature,
[1]
(ii) three readings were taken at each temperature,
[1]
(iii) the experiment at 80 °C was done last.
[1]
(e) Suggest how this experiment could be modified to show that the bubbles of gas given
off contain carbon dioxide.
[1]
(f) Suggest a suitable control experiment for this investigation.
[1]
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5
2
A student is investigating the characteristics of a converging lens by two different methods.
A converging lens is a lens that is thicker in the middle. It bends rays of light together so
that they can form an image on a screen, as shown in Fig. 2.1.
For
Examiner's
Use
Method 1
She sets up a converging lens so that light from a distant object produces a sharp image on
a screen as shown in Fig. 2.1.
lens
screen
rays of light
f
Fig. 2.1
(a) The distance f, from the screen to the lens, is called the focal length. Use a ruler to
measure the distance f.
f=
cm
[1]
Method 2
The student sets up the apparatus shown in Fig. 2.2. The light shines through the hole and
the screen can be moved until a sharp image of the illuminated object is formed.
screen
illuminated
object
lens holder
u
v
Fig. 2.2
She moves the lens so that distance, u, is 50.0 cm. She moves the screen until a sharp
image is seen. She measures distance, v, and records the value in Table 2.1. She repeats
this for different values of u.
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Table 2.1
u / cm
v / cm
u+v / cm
20.0
59.8
78.8
1196
30.0
30.1
60.1
903
45.0
22.7
67.7
1021
50.0
21.5
71.5
1075
For
Examiner's
Use
uv / cm2
40.0
Fig. 2.3 shows a diagram of the apparatus when distance u = 40.0 cm.
The diagram is drawn to the scale of 1 to 10. That means that 1 cm in the diagram is
actually 10 cm.
u
v
Fig. 2.3
(b) (i) Use a ruler to measure the distance for v in Fig. 2.3, to the nearest 0.1 cm.
distance =
cm
[1]
(ii) Convert this measurement to the actual value of v and complete the second
[1]
column of Table 2.1.
(iii) Complete column 3 of Table 2.1 by adding u and v.
[1]
(iv) Complete the final column of Table 2.1 by multiplying u and v.
[1]
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(c) (i) On the grid provided plot a graph of uv against u + v.
For
Examiner's
Use
Draw the best straight line.
1200
1100
uv / cm2
1000
900
800
60
80
70
(u + v) / cm
[2]
(ii) Find the gradient of your line.
Show clearly on the graph how you did this.
gradient =
[2]
(d) Your answer to (c)(ii) is the focal length of the lens.
Compare this to your answer in (a) and suggest the scale that Fig. 2.1 is drawn to.
[1]
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3
In this experiment a student is investigating how the rate of the reaction between
magnesium and acid is affected by the surface area of the solid. She sets up the apparatus
as in Fig. 3.1.
delivery tube
gas collected
clamp
measuring
cylinder
large
test-tube
water
acid
water bath
magnesium ribbon
Fig. 3.1
•
She removes the bung from the large test-tube and places 1 cm of magnesium ribbon
in the bottom of the test-tube.
•
She measures out 10 cm3 acid.
•
She starts the stopclock.
•
When the time on the stopclock reaches 10 seconds, she adds the acid to the test-tube
and quickly replaces the bung as tightly as possible.
•
She stops the clock when the volume of gas collected in the inverted measuring
cylinder is 10 cm3.
•
She subtracts 10 seconds from the time displayed on the clock, then records the result
in Table 3.1.
Table 3.1
length of magnesium / cm
time / s
1
37.5
2
19.0
rate / cm3 per s
3
4
She repeats the above steps using 2 cm of magnesium ribbon. She subtracts 10 seconds
from the time shown on the clock and records the result in Table 3.1.
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Examiner's
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9
(a) Fig. 3.2 shows the stopclock readings for lengths of magnesium 3 cm and 4 cm.
For
Examiner's
Use
Subtract 10 seconds from each and record the result in Table 3.1.
length of
magnesium = 3 cm
length of
magnesium = 4 cm
Fig. 3.2
[2]
(b) (i) For each length of magnesium, complete column 3 of Table 3.1 by calculating the
rate of the reaction using the formula
rate =
10
time
[1]
(ii) How does the rate of the reaction between magnesium and acid vary with the
length of magnesium ribbon?
[1]
(iii) Since the magnesium ribbon is thin, doubling the length of the ribbon
approximately doubles the surface area.
How does the rate of the reaction between magnesium and acid vary with the
surface area of the magnesium ribbon?
[1]
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(iv) The teacher said ‘The rate of reaction doubles when the length of the magnesium
ribbon is doubled’.
State whether the results show that the statement is correct or incorrect. You must
show which results support your statement.
[3]
(c) Suggest why she waited 10 seconds before adding the acid.
[1]
(d) The student suspects that the gas collected in the reaction is hydrogen.
Suggest how the student should test the gas collected in this experiment to show that it
is hydrogen.
[1]
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For
Examiner's
Use
11
4
The enzyme pectinase is used in industry for preparing fruit juices. Pectinase speeds up the
release of fruit juice from plant cells by breaking down the cell walls.
For
Examiner's
Use
A student used apples as the source of the plant cells. He wanted to produce a clear fruit
juice.
•
He placed some apple pieces and a little water in a blender and used this to produce a
smooth apple paste.
•
He then placed equal volumes of apple paste in each tube.
•
He then placed pectinase and water in the tubes as shown in Table 4.1.
•
He incubated the tubes at the temperatures indicated for ten minutes.
Table 4.1
tube number
apple paste / cm3
pectinase / cm3
water / cm3
temperature / °C
1
5
1
0
20
2
5
0
1
20
3
5
1
0
40
4
5
0
1
40
Results
appearance after incubation
appearance at start
all tubes
tube 1
tube 2
tube 3
tube 4
Fig. 4.1
(a) (i) Pectinase was not included in tubes 2 and 4.
Explain why tubes 2 and 4 were included in the experiment.
[1]
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(ii) Explain why both tubes 2 and 4 were used for this purpose.
For
Examiner's
Use
[1]
The student looked carefully at tube 3 after incubation. The apple paste had become less
cloudy than in the other tubes.
(iii) Compare the appearance after incubation of tube 1 with the appearance of all
tubes at the start and record your observation.
[1]
(iv) Compare the appearance after incubation of tube 3 with the appearance of tube 1
after incubation and record your observation.
[1]
(v) Explain the difference between tube 1 and tube 3 after incubation.
[1]
Although fruit juice had been produced in tube 3 the juice was still rather cloudy. The
student suspected that starch from the broken apple cells was suspended in the juice.
(b) (i) Suggest a test he could carry out on the contents of tube 3 to find out if starch is
present.
Describe the test and a positive result.
[1]
(ii) The student found that starch was present. Name an enzyme he could use that
could break down the starch.
name of enzyme
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[1]
13
(iii) The student modified his original experiment to make the fruit juice as clear as
possible.
For
Examiner's
Use
Describe in detail what he did and how he could prove that the enzyme named in
(b)(ii) was effective.
[3]
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5
(a) A motor manufacturer is testing his new electric car.
The driver is given instructions on how to drive over a set distance on a special test
track, as shown in Fig. 5.1.
Poles are placed 10 m apart and a photograph of the position of the car is taken every
second.
distance from
start (m)
90
80
70
60
50
40
30
20
10
0
Fig. 5.1
The distances for one test run are recorded in Table 5.1.
Table 5.1
time / s
0
1
2
3
4
distance / m
0
8
18
34
52
5
6
99
7
8
9
10
161
199
239
(i) Use Fig. 5.2 to record in Table 5.1 the distances travelled after 5 and 7 seconds.
Take your measurement from the front of the car.
90
80
70
60
50 m
130
time = 5 seconds
120
110
100
time = 7 seconds
Fig. 5.2
© UCLES 2013
[2]
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90 m
For
Examiner's
Use
15
(ii) On the grid provided plot a graph of distance / m (vertical axis) against time / s.
For
Examiner's
Use
Draw a smooth curve of best fit.
[3]
(iii) Explain what the shape of the graph tells you about the motion of the car.
[1]
(iv) Calculate the average speed of the car over the first six seconds.
[1]
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Fig. 5.3 shows sketch graphs of 3 more tests runs.
distance
For
Examiner's
Use
A
B
X
C
time
Fig. 5.3
(b) (i) State in what ways test runs A and B are similar and different.
similar
different
[2]
(ii) Suggest what may have happened at point X in test run C.
[1]
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Please turn over for Question 6.
© UCLES 2013
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6
(a) Fig. 6.1 shows words and phrases about different anion tests cut from a page of a
student’s note book.
Use a ruler to construct a table, showing each anion, test reagent and result which
identifies the anion.
Fig. 6.1
[4]
© UCLES 2013
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For
Examiner's
Use
19
(b) (i) The teacher asks the student to make a dry sample of copper sulfate crystals from
sulfuric acid and powdered copper oxide.
The student begins by using these chemicals to prepare a solution of copper
sulfate.
Describe in detail how the student prepares this solution.
[3]
(ii) She leaves the copper sulfate solution prepared in (b)(i) in a warm place to
remove the water.
Name this process by which the water leaves the solution.
process
[1]
(iii) She washes and dries the crystals from (b)(ii).
What colour are the crystals?
colour
[1]
(c) Copper oxide is an example of a base.
Copper sulfate, barium chloride and silver nitrate are all examples of another group of
chemicals.
Name this group.
name
© UCLES 2013
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[1]
For
Examiner's
Use
20
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© UCLES 2013
0654/63/M/J/13